Controlling diamond film surfaces and layering

Abstract

A method comprising: providing at least one first diamond film comprising polycrystalline diamond, e.g., nanocrystalline or ultrananocrystalline diamond, disposed on a substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness, removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness, optionally patterning the second diamond film to expose substrate regions and, optionally, depositing semiconductor material on the exposed substrate regions, and depositing a solid layer on the second diamond film to form a first layered structure. Applications include for example dielectric isolation in the semiconductor industry, as well as surface acoustic wave devices, scanning probe microscope, and atomic force microscope devices.

1. A method comprising:
 providing a substrate; 
 depositing at least one first diamond film comprising UNCD onto the substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness; 
 after the step of depositing the at least one first diamond film on the substrate, removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness, and 
 depositing a solid layer on at least a portion of the second diamond film to form a first layered structure. 
 
     
     
       2. The method of  claim 1 , wherein the solid layer comprises an electrical insulator, an electrical conductor, a semiconductor, or a piezoelectric material. 
     
     
       3. The method of  claim 1 , wherein the solid layer comprises an oxide or a metal. 
     
     
       4. The method of  claim 1 , wherein the solid layer comprises additional polycrystalline diamond. 
     
     
       5. The method of  claim 1 , wherein the substrate is a semiconductor substrate. 
     
     
       6. The method of  claim 1 , wherein the substrate comprises a sapphire layer and a silicon interlayer. 
     
     
       7. The method of  claim 1 , wherein the first thickness is about 200 nm to about four microns. 
     
     
       8. The method of  claim 1 , wherein the second thickness is about 10 nm or less thinner than the first diamond film thickness. 
     
     
       9. The method of  claim 1 , wherein the second thickness is substantially the same as the first thickness. 
     
     
       10. The method of  claim 1 , further comprising the step of bonding the solid layer of the first layered structure to a second layered structure comprising a semiconductor substrate and a bonding layer. 
     
     
       11. The method of  claim 1 , further comprising the steps of (i) bonding the solid layer of the first layered structure to a second layered structure comprising a semiconductor substrate and a bonding layer, and (ii) thinning the semiconductor substrate to form a semiconductor device layer. 
     
     
       12. The method of  claim 1 , comprising the step of patterning the second diamond film to expose substrate regions and depositing semiconductor material on the exposed substrate regions. 
     
     
       13. The method according to  claim 1 , wherein the second diamond film has fewer than about 10 asperities per square centimeter, wherein the asperities have a height/width ratio of greater than about 1:1 and a height above the average height of surface of the film of greater than about three times the average surface roughness. 
     
     
       14. The method of  claim 1 , wherein the removal step is carried out for about 60 minutes or less. 
     
     
       15. The method of  claim 1 , wherein the solid layer is a solid layer of silicon dioxide or copper, and the substrate is a silicon substrate. 
     
     
       16. A method comprising:
 providing a substrate; 
 depositing at least one first diamond film comprising UNCD onto the substrate, wherein the first diamond film comprises a surface with an unpolished average roughness of less than 50 nm and having a first diamond film thickness; 
 after the step of depositing the at least one first diamond film on the substrate, processing the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness and the surface roughness is less than 10 nm; 
 optionally patterning the second diamond film to expose substrate regions and, optionally, depositing semiconductor material on the exposed substrate regions; and 
 depositing a solid layer. 
 
     
     
       17. The method of  claim 16 , wherein the processing comprises polishing the surface with an abrasive for less than 60 minutes. 
     
     
       18. A method comprising:
 fabricating at least one semiconductor device comprising device elements in a semiconductor device layer and a substrate, wherein the fabrication comprises at least one step comprising forming a UNCD film which is adapted for electrically insulating device elements from the substrate and also adapted for providing thermal conductivity pathways between device elements and the substrate, wherein the diamond film as formed has an Ra of about 20 nm or less and has a first thickness, and is subjected to a diamond removal step which comprises removing about 25 nm or less of diamond from the first thickness. 
 
     
     
       19. A method comprising:
 providing a substrate; 
 depositing at least one first diamond film comprising UNCD onto the substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness; 
 after the step of depositing the at least one first diamond firm on the substrate, removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness, and wherein the second diamond film has an average grain size of about 20 nm or less and an average surface roughness of about 50 nm or less; and 
 depositing a solid layer on the second diamond film to form a first layered structure. 
 
     
     
       20. A method comprising:
 providing a substrate; 
 depositing at least one first diamond film comprising UNCD onto the substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness, 
 removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness, 
 depositing a solid layer on the second diamond film, wherein the material of the solid layer is selected to be adapted for direct bonding to another layer of the same material. 
 
     
     
       21. A method comprising:
 providing a substrate; 
 depositing at least one first diamond film comprising UNCD onto the substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness, 
 removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness; 
 patterning the second diamond film to expose substrate regions; 
 depositing semiconductor material on the exposed substrate regions; 
 depositing an additional third layer of polycrystalline diamond on the first diamond film and semiconductor material; and 
 depositing a solid layer on the third diamond film. 
 
     
     
       22. A method comprising:
 providing at least one first diamond film comprising polycrystalline diamond disposed on a substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness; 
 removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness; optionally patterning the second diamond film to expose substrate regions and, optionally, depositing semiconductor material on the exposed substrate regions; and 
 depositing a solid layer on the optionally patterned second diamond film to form a first layered structure, 
 wherein the solid layer is a solid layer of silicon dioxide or copper, 
 wherein the diamond film comprises UNCD, and 
 wherein the substrate is a silicon substrate. 
 
     
     
       23. The method of  claim 1 , wherein the solid layer is a solid layer of silicon dioxide or copper. 
     
     
       24. The method of  claim 1 , wherein the substrate is a silicon substrate. 
     
     
       25. A method comprising:
 providing a substrate; 
 depositing at least one diamond film comprising UNCD onto the substrate; 
 performing an asperity removal step on the at least one diamond film comprising UNCD for a period of 60 minutes or less; and 
 depositing a solid layer on at least a portion of the at least one diamond film to form a first layered structure. 
 
     
     
       26. The method of  claim 25 , wherein the asperity removal step is performed for a period of 30 minutes or less. 
     
     
       27. The method of  claim 25 , wherein the asperity removal step is performed for a period between 2 minutes and 10 minutes. 
     
     
       28. The method of  claim 25 , wherein the asperity removal step is performed for a period between 1 minute and 10 minutes. 
     
     
       29. The method of  claim 25 , wherein the asperity removal step comprises a chemical mechanical planarization process.